Tattoos have been used in almost every culture throughout history. They have been found on a five thousand year old human mummy, and decorated figurines suggest their use at least fifteen thousand years ago. Tattoos have been used for many purposes including identity, beauty, artistic and spiritual expression, medicine, and magic.
In the United States, statistics are not kept on tattooing but the practice has apparently been growing in popularity for the past few decades. The majority of tattoos are apparently obtained by people under forty years of age, including a significant proportion of teenagers. An estimated 2 million people are tattooed every year.
In the U.S. today, the uses of tattooing have expanded to include not only the familiar artistic tattoo, but also permanent makeup, for example, permanent eyebrows, eyeliner, lip liner, and lip color; corrective or reconstructive pigmentation, for example, repigmentation of scar tissue or areola reconstruction on mastectomy patients; medical markings, for example, marking gastrointestinal surgery sites for future monitoring; and identification markings on animals, for example, pedigree “tags” on purebred pets.
The tattooing procedure consists of piercing the skin with needles or similar instruments to introduce an ink that includes small particles of pigment suspended in a liquid carrier. During the healing process, some particles of pigment are sloughed from the skin surface and others are transported to the lymphatic system. What one sees as the tattoo are the remaining particles of pigment located in the dermis where they are engulfed by phagocytic skin cells (such as fibroblasts and macrophages) or are retained in the extracellular matrix.
To create a permanent tattoo one must implant pigments that are not dissolved or digested by living tissue. Primitive pigments probably consisted of graphite and other carbon substances. Modern pigments also include inorganic metal salts and brightly colored organometallic complexes.
Tattoo ink ingredients have never yet been regulated or fully disclosed to the public. Ink composition and pigment sources remain trade secrets. Allergic reactions to these unknown and/or undisclosed substances, rare but in some cases severe, have been reported at the time of tattooing, well after the time of tattooing, and after exposure to sunlight or laser treatments.
The long-term health effects, including potential toxicity and/or carcinogenicity of tattoo pigments, have not been studied and are not known. Unfortunately, these pigments, chosen for their permanence, are believed to remain in the body for life, concentrated in the lymph nodes, even if the visible tattoo is “removed” from the marked area, for example, by laser treatment.
A widely recognized problem with tattoos is that they cannot be easily removed. One survey indicated that about half of all Americans with tattoos at some point wish they could remove them. Dissatisfaction can stem from undesired social disapproval; from the appearance of a tattoo that may be poorly executed, out-of-style, or inaccurate (commonly in the case of name-containing vow tattoos); or from changes in the wearer's self-perception or lifestyle, which are especially likely for the increasing number of young customers.
Tattoo “removal” methods have included overtattooing without ink, dermabrasion, and surgical excision, all of which usually leave unacceptable appearance and/or scarring. The use of these removal methods was recorded as early as the first century A.D. in Rome, when soldiers returned from barbaric regions with tattoos that were unacceptable to society.
In fact, there had been no significant technological advances in tattoo removal methods until the 1960s when Dr. Leon Goldman pioneered the use of pulsed lasers. This method was improved in the 1980s by Dr. R. Rox Anderson, and has since become widely practiced. Removal can now also be achieved using variable-wavelength intense pulsed light sources (flash-lamps).
Ideally, short, powerful light pulses are absorbed specifically by tattoo pigment particles with little or no absorption by surrounding tissue, thereby causing the particles of pigment to break apart with minimal damage to neighboring skin structures. Skin injury is extremely local and scarring is uncommon. Instantaneously, some particles of pigment are apparently broken into pieces which have far less optical absorption than the original particles, and thus are less visible. During the healing process, many particles are physically removed from the tattoo site while others remain in the dermis as a residual tattoo.
Despite advantages over older methods, laser or flash-lamp removal of standard tattoos is not ideal. A treatment course requires an average of approximately eight laser treatments at a cost of several hundred dollars apiece. The treatments must be spaced at least one month apart and can be painful. Because a laser must be chosen for absorption of its emission wavelength by the particular pigment, multiple lasers are needed to treat multicolored tattoos effectively; however, a removal practitioner's office may not offer the optimal laser(s) to treat a specific tattoo. Certain pigments, including many greens, remain difficult to remove, and there is currently no commercially available tattoo removal laser which effectively treats most yellow pigments. Intense visible light sometimes targets the skin's natural epidermal pigment, melanin, resulting in temporary or permanent hypo- or hyperpigmentation, especially in dark or tanned skin, and/or hair loss in the area. In addition, some tattoo pigments undergo color changes in response to treatment. For example, inks used for permanent makeup often contain certain iron, titanium, or other oxides which are irreversibly blackened upon exposure to Q-switched lasers, and cannot always be removed by further treatments.
After the treatment course, most patients can expect that a tattoo will not be prominently visible or recognizable, but it is unusual to be able to restore the skin to its original pre-tattoo appearance. Because of the numerous drawbacks, only a fraction of those people who are unhappy with their tattoos pursue tattoo removal.